Pump



Sept. 1, 1936. I E A NK 2,053,027

v PUMP Original Filed Jan. 11, 1935 5 Sheets-Sheet l S 1936- E. A.FRANks 2,053,027

PUMP

5 Sheets-Sheet 2 Original Filed Jan. 11, 1935 Sept. 1, 1936. E A, FRANKS2,053,921

' PUMP Original Filed Jan. 11, 1955 5 Sheets-Sheet 3 Sept. 1, 1936. E.A. FRANKS PUMP 5 Sheets-Sheet 4 Original Filed Jan. 11, 1935 Spt. 1,193a PUMP Original Filed Jan. 11, 1935 5 Sheets-Sheet 5 Patented Sept.1, 1936 mm srsrs PUMP Ernest Arthur Franks, Whitchurch, Wales Originalapplication January 11, 1935, Serial No. 1,400. Divided and thisapplication September 9, 1935, Serial No. 39,851.

October 30, 1934 12 Claims.

This application is a division of my application No. 1,400, filedJanuary 11th, 1935.

This invention relates to pumps and more especially to pumps forsupplying fuel to Diesel and other compression ignition engines.

The invention is particularly concerned with an arrangement whichcomprises two pistons dis.- charging to a common discharge and operablethrough followers by rotary cams at least one of the followers beingmovable to advance or retard the follower with respect to its cam so asto vary the phase relationship of the two pistons. The main object ofthe present invention is to provide improved means whereby the fuelsupplied by the two pistons can be regulated.

According to the present invention in a fuel pump which comprises twopistons discharging to a common discharge and operable, throughfollowers by .rotary earns, a movable regulating member being providedfor at least one of the followers to advance or retard the follower withrespect to its cam and so to vary the phase relationship of the twopistons. The or each movable follower is so slidably mounted in theregulating member as to be constrained to move in the same direction asthat of its associated piston while the regulating member is constrainedto move in a plane which is transverse with respect to the saiddirection of movement of the piston. In Diesel or compression ignitionengines,;it is necessary that the delivery be under control and capableof quick and definite regulation as between-maximum and no delivery, itbeing further. necessary that the point of commencement of delivery inrelation to the engine cycle be under control so as to get the bestfiring point for different loads on the engine.

To effect this there is provided a pump element having two pistons (or apiston and slide valve) driven by mechanism which is adapted toreciprocate the pistons in an adjustable out-ofphase relationship. Thesetwo pistons open into a common delivery chamber so that while thepistons are operating in the same sense, both operate to deliver fuel,but when one piston operates in the reverse sense, the delivery of oneis taken by the other so that no effective delivery is established: byalteration of the two phases simultaneously the timing of effectivedelivery is adjusted and by altering the phases relatively to oneanother, the efiective delivery is adjusted.

Where the total volume required to be delivered by the pump would beextremely small when divided-between two pistons, one of the pistonswhich may be larger thanthe other could act as In Great Britain thedelivery pump and the other as a piston or spill valve. The constructionof both pistons would be the same excepting that as the piston formingthe piston valve was made smaller in area the stroke would be increasedto give the e same volume as the delivery pump or the profile of a camfor operating this piston be so formed a torelea e t e p st n forming te Spill valve at the required moment for the cessation of de livery ofthe fuel. .0

- .In any a e is de rab e t at t i o ing as the piston or spill valveshould have a clearance volume somewhat in excess of the delivery pistonproper so as to cause a partial vacuum in the chamber common tothe twopistons 1.5 at the instant of cut off. This can be effected either by adifference in pump diameter or in the stroke as allowed by the camprofile.

The invention is illustrated in the accompanying drawings as applied toa pump incorporating the invention described and claimed in the pendingapplication Serial No. 1,400, filed January 11, 1935.

In the drawings, Figure 1 is a longitudinal section partly in elevation,Figure 2 a section on the line IIII Figure 1, Figure 3 a section on theline III-III Figure 1, Figure 4 a detail plan view, Figure 5 a sectionon the line V,-V Figure 1, Figure 6 a detail elevation and Figures '7and 8 views similar to Figure 4 of a modification.

The arrangement illustrated in the accompanying drawings is a multi-unitpump arrangement (i. e. an arrangement comprising a plurality of pumpunits) and while for convenience reference has been made to the parts ofone unit, 35 in the drawings corresponding parts of I the various unitshave been given corresponding numerals.

In the drawings each pump .element consists of two diameter rods-l, 3and I, 3' working in two diameter cylinders 2, 2', 5, 5, the smallerdiameter parts of the cylinders 2 and 2' opening into a common chamber.4 having a spring loaded outletvalve l2. The valve I2 is carried by aplug I2 having-a tapered lower face co-operating with a tapered washer12 to provide an air-tight joint. The rods are formed of two diametersfor the purpose described in the specification of the application SerialNo. 1,400, but for the purposes ofthelpresent invention it is merelynecessary to discuss the smaller diameter parts I and I" of the rods andto regard them as two pump elements discharging into a common chamber 4.The'pa-rts 2, 2 of the cylinders in which the pistons I and l operatecommunicate through a valve l3 and a passage H with a chamber [0, thevarious chambers being interconnected by a passage l6 and these chambersare supplied with fuel in the arrangement shown by the larger diameterparts 3, 3 of the rods l, I which feed fuel from a passage 1 and passage6 to the chambers it through passages 8 and past non-return valves 9. v

The pumping effect is obtained by reciprocating the rods forming thepistons I, 3 and l, 3' by a cam 25 through intermediate members orfollowers 21, 2?.

The intermediate members or followers 21, 21"

are of square cross section and are mounted to reciprocate in the samedirection asv the pistons I and l' in apertures formed between'the twoopposed end walls of square aperturesformed in sliding plates orregulating members 28, 28 and two opposed side or filling pieces 28 28which are interposed between the members 21, 21' and the side walls ofthe apertures in the plates 28, 28' lying tangentially with respect tothe shaft 29 on which the cam 25 is mounted and at right angles with theaxis of the pump rod. The plates 28, 28' are movable in a directionwhich is in a plane transverse with respect to the direction of movementof the pistons.

The 'tworods forming the piston I, and!" are I spring loaded so astohold them against their intermediate members 2?, 2i and these membersagainst their cam 26, this preferably being 'effected by 'a' singlespring 30 which is coiled around a stationary'pin 3i and has its centralportion 32 exte'nded to form areaction point and its two ends 33received within apertures in the respective rods. 5

The movement of the sliding plates 28, 2B is regulated by a tongue orprotuberance 34, 34 extending across the sliding plateat an inclinationto the axis of the cam shaft, the tongues engaging grooves formed in aplane parallel with. the plane of movement ofthe plates 28, 28 but in atransverse direction with respect to the direction of movement of theplates 28, 28;

With the construction described it will be seen that by moving thesliding plates 28, 28 the intermediatemembers 21, 21' are moved to beadvanced or retarded with respect to the cams and that this movement ofthe plates is effected by moving the control'b'ars 35, 35'.

'Any movement will, of course, cause an earlier or later movement (withrespect to the cam) in a reciprocating motion of the piston associatedwith the cam.

'The-degree of sensitiveness of adjustment is a measure of the angle ofthe grooves or tongues. The smaller the angle formed between a linepassing through the centre of the tongue and a line representing thedirection of 'movement of the bars, the greater will be the length oftravel of the associated bar 35 or 35' to effect a similar movement ofthe sliding plates 28, 28. And, further, the smaller the angle asmentioned the less will'be the reaction of the cam thrust on the slidingplates and with a very small angle and a long travel of the control bars35, 35 the reaction is very small and the control takes place in a planeapproaching right angles to the plane of reaction of the sliding plates.l

Any thrust imparted to the control bars in a horizontal direction may betaken up either by the walls of the casing of the apparatus, or wherenecessary by rollers or ball bearings 31, and the bar sliding in adirection at right angles to such thrust, is free from any reaction. Thesliding able upon the quantity of fuel to be delivered, thusautomatically ensuring the fuel injection meeting the load placed uponthe engine. An arrangement employing a gear wheel 33 is shown in Figure4 and the angles of the grooves in the two controLbars bear such a ratiothat a movement impartedto one control bar 35 although transmittedequally to the other control bar 35' causes a smaller movement of onesliding plate 28 than of the other 28, and hence the change in positionof one intermediate member 21 with respect to the cam 26 is less thanthe change of the other intermediate-member 21 with respect to the cam25. Thus, suppose the period of delivery of the piston I. is toextendIover 'say'15 and it is desired to have control of 6' advance ininjection, then the control bar 35 for the piston i will have to controlover 21 whilst the control bar 35 for the piston I-will control overonly 6. The ratio of the angle of the slots in the control bars 35, 35would thus be 6:21.

Alternatively the arrangement shown in Figure '7 could be employed togive a similar result, the desired ratio in the movements of the plates28, 28 being obtained by having a link 43 by which a movement of thecontrol bar 35 is transmitted to the plate 28' in theratio of 21:6, theangles of the grooves in the plates being equal as is shown.

The regulation of delivery as described is effected by hand for quickoperation but for regular running and the other conditions imposed onthe fuel supply there is provided a governor.

The governorconsists of a liquid supply, preferably lubricating oil oflow viscosity, to a cham-' her in which reciprocates a piston or thelike on one control bar, this bar having a reaction spring. There isalso provided in the liquid supply a controlled orifice such as a needlevalve or the like.

It is known that with a constant volume delivcry pressure rises as theoutlet is reduced and this variation in pressure is employed to causereciprocation of the piston connected to the control bar.

' A corollary of thisis that with a fixed size orifice variations inquantity will cause variations in pressure and this also is made use ofin causing the reciprocation of the control bars.

Liquid supply, which is effected at a ratio proportional to the speed ofthe engine, is obtained in the arrangement shown by two plungers 4|, 42which are positively reciprocated by cam grooves 43, 44 in discs securedto the shaft 29 the plungers having pins 46 entering the cam grooves.These plungers when at one end of their stroke uncover passages 47opening to a supply chamber 48 to allow liquid toflow into the plungers:this liquid is forced by the plungers 4t, 42 when mov ing on theirdelivery stroke past non-return valves 49, 50 to a chamber 5| whichiscommon to the plungers and this chamber is provided with theregulatable orifice indicated at 52 and with a connection 53 to thecylinder 54 in which reciprocates the piston 55 connected to the controlbar 35. The orifice is regulated by a valve 56 which has a screwthreaded shank 51 so thatby rotating the shank, the orifice is coveredor uncovered to a greater. or lesser extent, the orifice opening intothechamber48. w

It:wi1l now be ;seen:that if:fthe valve-56 be operated by closing .or.opening; the pressure .applied by liquid to the piston :willincrease ordecrease and the control bars'willqbe caused to move, thus. increasingor decreasing the quantity of. fuel delivered to the engine;

,If the valve be set,- then increase or decrease inrthe speed of theengine: will. cause greater or lesser pressure to: be applied to thepiston 55 and hence to the control bars and tending to cause-steadyingof the engine running' Such a governor can be made extremely sensitiveand quick'in control by the correct proportions of the components.

(2) By fixing one control bar and allowing the. other to be moved,afixed moment for commencement of delivery and variable moment forcessation of delivery would be obtained. This can be obtained by anarrangement as shown in Figures 4 and '7 but omitting the gear wheel 39or the link 40, the movable control bar being operated by hand by beingcoupled to some form of hand control, or worked by a governor such asthat described. The object of providing the other (or normally fixed)control'bar in this case is to provide for adjustment from time to timeand to meet the various conditions of different engines: .or anarrangement as shown in Figure 8 can be "employed inwhich case only onecontrol bar 35is employed, the other control bar being omitted and thesliding pieces 28' are secured by pegs 28 (3) Both control bars free tomoveindependently. This would give a variable moment for commencement ofdelivery and a variable moment for cessation of delivery.

The double piston arrangement described also possesses the furtheradvantage of distributing the power required to operate the'pump.

As has been stated the drawings incorporate apparatus in accordance withthe invention described and claimed in the co-pending application SerialNo. 1,400 and to effect this the pistons l and I are made a slack fit intheir cylinders and the pistons 3, 3"feed fuel not only to the chambersl0 but also to the clearance left by the slack it. In addition thechamber 10 is in communication with the passage lfi extending through achamber l6 and passage I6 and tube 20 to a vent formed by a springloaded valve I! which opens when the pressure of the fuel fed by thesecond piston 3 exceeds the spring loading: the opening of the valveplaces the passage l6 and hence the chamber l0 open :to a'lowpressure'vent' passage l8 and the fuel displacement of the second piston3 is arranged to be in excess of the requirements per cycle. Thus excessfuel, together with air, is allowed to pass through the vent II' whichremains .open' until the second piston 3, ceases to displace fuel.

Furthermore, as is also described and claimed in the said application,Serial No. 1,400, the-tube 20 extends into a second tube 2! dependingfrom a block 22 carrying the valve H the second tube 2| extending into atubular casing 23 closed at .its upper end by the block 22 the casingbeing. closed at its lower end; the first tube 29 is spaced at its,upper. end fromthe block .22 and the lower end of the second tube 2] isspaced from the tubular casing; mercury or other liquid indicated at '24and which will preventthe passage of air orother'gas, "and'will notreact with the fuel is contained in the annulus between the secondtubeZI and-the casing 23 and between the second tube 2l-. and the firsttube 20 and it will be seen that air trapped above the mercury in theannulus between the second tube 2! and the casing 23 will be compressedwhen fuel pressure conditions rise and the air will react to maintainthis pressure on the fuel. The interposition of mercury or other liquidbetween theairand the fuel prevents the air from passing to and mixingwith the fuel. In order to prevent the spilling of mercury should thedevice become inverted, the first tube may have at its upper end a smallorifice which, while allowing fuel to pass, will prevent or offer alarge resistance to the passage of mercury.

58 is a reservoir from which lubricating oil is supplied to a passage 15for supplying oil to grooves I4, M in the pistons 3, 3'. This iseffected by a further plunger 59 which is held by. a spring 60 inengagement with a cam BI on the shaft 29. This plunger during itssuction stroke draws oil from the chamber 58 past a nonreturn valve 62and during its delivery stroke delivers the oil to the passage l5 past anonreturn valve 63. In order to prevent the generation of unduly highpressure, a relief valve arrangement is provided. This relief valve isin the form of a piston 64 which carries the valve 62 and is urged by aspring 66, this spring being such as to allow the piston to be displacedagainst the spring 66 when the pressure generated by the plunger exceedsa predetermined value.

In order to prevent the pressure the passage l5 from dropping anexcessive amount when the plunger 59 moves on its suction stroke a plugl5 closing the end of the passage 15 is arranged to form a housing vfora springloade'd plunger l5 which reacts to maintain pressure in thepassage l5. Alternatively a spring loaded diaphragm could be employed.Said plunger F provides resilience in the system so that the capacity ofthe system may vary,. the plunger being spring loaded for this purposeso as to give or yield when thecapacity of the system is required toincrease. l

It is well known that the small pocket of air in a pumping systemprevents a "snappy" cut-off in the delivery and it is further well knownthat air lodged in the system will prevent the functioning of a pump. I

To ensure any air in the pump system being expelled without thenecessity for turning the engine supplied by the pump system a smallhand operated piston pump 61 .is provided in communication ;through anon-return valve 6.8 with the fuel supply passage 1 and through anon-return valve 69- with the storage pressure side of the pumps (i. e.with the passage 15) this hand operated pump forces fuel through all thepassages and drives air out through the spring loaded ventl'l. I

It is preferred to form the casing of the pump assembly. in two partswhich are held together by dove-tailed recessed plates :70, thedove-tailed sides being slightly tapered, which engage projections Hwhich are formed. coniointly by the two parts and are similarly.taperedz. thus, by forcing the plates 10 on to the projections 11, thetwo parts are drawn firmly together.

' It will be obvious that the invention isunot limited in itsapplication to a multiple pump nor to a pump incorporating the;invention according to the'specificatiomserial No. 1,400.

What I'olaimis-: :1

'1'. .In'a fuel pump, two reciprocablepump elements, a conduit into-which both elements discharge, rotary cam mechanism reciprocating thepump elements, followers interposed-between the cam mechanism-and pumpelements, guide members in which thefollowers are slidably guided andconstrained-to movein the same direction as the respective pump elementsm'eans mounting atleast'one of the 'guide'members for movement in aplane transverse with respect to the direction of ''movement of thefollower guided thereby, and means to effect movement of the movableguide member tc vary the" position of the 'asso-. ciated follower withrespect to the cam mecha 2. Ida fuel pump, two reciprocabl'e pumpelements, at conduit into which both elements discharge, rotarycam'mechanism reciprocating the pump elements,'-followers interposedbetween the cammechanismand pump elements, guide members in whichthe-followers areis'lidably guided and constrained to move in the samedirection as the respective pump elements, anti-friction means mountingat least one of the guide members for movement in a plane transversewith respect to ,the direction of movement of the follower guidedthereby, and means to effect movement of the movable guide member tovarythe position of the associated follower with respect to the cammechanism.

3'. Ina fuel'purnp, tw'o reciprocable pump elements, a conduit intowhich both elements discharge, rotary cam mechanism reciprocating thepump elements, followers interposed between the cam mechanism and pumpelements, guide'membersin which the followers are slidably guided andconstrained to move in the same direction as the respective" pumpelements, means mounting at least one of the guide members for'movementin aplanetransverse with respect tothe direction'of movement of thefollowerguided thereby, a control member for the movable guide member,me'ans' mounting the control member for movement in a plane parallelwith that of the guide member and in a direction'atright angles to thedirection of movement of the guide 'memher, and an inclined tongue andgroove connection between the control member and the guide m emher sothat movement of the control member effects movement of the guidememberto vary the position of the associated follower withrespect to thecammec'hanism;

4; In a'fuel pump, two reciprocable pump elements, a conduit into whichboth elements dis charge, rotary cam mechanism reciprocating the pumpelements, followers interposed between the cam mechanism and pumpelements, guide members in which the followers are slidably' guided andconstrained to move in the same direction as the respective pumpelements, anti-friction means mounting at least one of the guide membersfor movement in a plane transverse with respect to the direction of themovement of the follower guided thereby, a control member for themovable guide member, anti-friction means mounting the control memberfor movement in a plane parallel with that of the guide member and in adirection at right angles to the direction of movement of theguidemember, and an inclined tongue and groove connection between thecontrol member, and the guide member so that movement of the controlmember efiects movement of the guide member to vary the positionoftheassoci+ at'ed follower withlrespect to the cam mechanism. -45. In afuel pump," two reciprocable' pumpv elements, a conduit into whichboth-elements dis-v charge, rotary eam mechanism reciprocating the pumpelements, followers interposed betweenithe cam mechanism. and .thepump-elements, guide members'in-"which the followers are guided to movein the'same direction as the associated pump elements'means mounting theguide members for movement in atplane transverse with respect to thedirection of :movement of the followers guid ed thereby, and meanseffecting movement of the guide members. in unison to.vary.the phaserelationship between the two followers. '1

6. In a fuel pump, two reciprocablepump elements,-a conduit into, whichboth elements discharge, rotary cammechanism reciprocating the pumpelements; followers interposed between the cam mechanism and .theipump.elements, guide members in which the followers areguided to move in thesame direction'as the'associa'ted pump elements, means "mounting theguide members for movement. in a plane. transverse with respect to thedirection of movement of thefollowers guided thereby, control'membersone for each guide member; ..means guiding the control members formovement in a plane parallel with that'of the associated guide memberand in adirection at right angles-to the direction of movementof theassociated guide =member, and inclined tongue and groove connectionsbetween control members and the guide members and meanseifecting simul-vtaneous movement ol thecontrcl members to vary the phaserelationshipbetween the two followers.

7. In afuel pump, two reciprocab-le pump elements, a conduit intowhichbothelements dis-. charge, rotary cam mechanism reciprocating the pumpelements, followers interposed between-the cam mechanism *and'the pumpelements, guide members in which the; followers are guided to move inthe same direction as the associated pump elements, anti-friction meansmounting the guide members for movement in aplane transverse withrespect tothe direction of movement .of the followersguided thereby,.control members one for each-guide member,anti-friction means guidingthe control members for movement ina plane parallel with that of'the'associated guide memher, and in adirection-at rightangies to thedirection of movementof the associated guide member, and inclined tongueandgroove connections betweenicontrol members and the guide members andmeans effecting simultaneous movement of the control members to'vary thephase relationship between the two followers- 8. Two pistons, two,cylinders supported in parallel relationship and in which the twopistons are reciprocable, 'the cylinders openinginto a terposed'betweenthe cam and the pistons, guide members in which the followers areconstrained poevel ci n gs rsm ei t e control members into movement ofthe guide members to vary the setting of the followers relatively to thecam.

9. A plurality of pumps each comprising two pump elements discharginginto a common discharge, rotary cam mechanism reciprocating the pumpelements, followers interposed between the cam mechanism and the pumpelements, guide members in which the followers are slidably guided andconstrained to move in the same direction as the respective pumpelements, means mounting at least one of the members for movement in aplane transverse with respect to the direction of movement of thefollower guided thereby, a control member for corresponding movableguide members of all the pumps, means guiding the control member formovement in a plane parallel with that of the guide members and in adirection at right angles thereto, and

means converting movement of the control member into movement at rightangles thereto of the said movable guide members to vary the setting ofthe corresponding followers of the plurality of pumps with respect tothe cam mechanism.

10. A plurality of pumps each comprising two pump elements discharginginto a common discharge, rotary cam mechanism reciprocating the pumpelements, followers interposed between the cam mechanism and the pumpelements, guide members in which the followers are guided to move in thesame direction as the associated pump elements, means mounting the guidemembers for movement in a plane transverse with respect to the directionof movement of the followers guided thereby, two control members oneeach for the corresponding guide members of the plurality of pumps,means guiding the control members for movement in a plane parallel withthat of the guide members and in a direction at right angles to thedirection of movement of the guide members, means converting movement ofthe control members into movement at right angles thereto of the guidemembers to vary the setting of the corresponding followerssimultaneously, and means transmitting movement from one control memberto the other control member.

11. A plurality of pumps each comprising two pump elements discharginginto a common discharge, rotary cam mechanism reciprocating the pumpelements, followers interposed between the cam mechanism and the pumpelements, guide members in which the followers are slidably guided andconstrained to move in the same direction as the respective pumpelements, means mounting at least one of the members for movement in aplane transverse with respect to the direction of movement of thefollower guided thereby, a control member for corresponding movableguide members of all the pumps, means guiding the control member formovement in a plane parallel with that of the guide members and in adirection at right angles thereto, and inclined tongue and groove meansconverting movement of the control member into movement at right anglesthereto of the said movable guide members to vary the setting of thecorresponding followers of the plurality of pumps with respect to ity ofpumps, means guiding the control members for movement in a planeparallel with that of the guide members and in a direction at rightangles to the direction of movement of the guide members, inclinedtongue and groove means converting movement of the control members intomovement at right angles thereto of the guide members to vary thesetting of the corresponding followers simultaneously, and meanstransmitting movement from one control member to the other controlmember.

ERNEST ARTHUR FRANKS.

